1. Field of the Invention
The present invention relates to a control and surveillance system for a prepayment public telephone connected to a telephone central office via a telephone line. A communication may be prepaid by means of coins or a credit card.
2. Description of the Prior Art
The problems involved in the management of public telephones in the face of increasing acts of vandalism and fraud lead to a series of observations calling into question current strategy and highlighting the weak points of known systems. The system embodying the invention is designed taking account of the following observations.
In order to combat fraud were developed increasingly complex public telephones, becoming more and more expensive and required increasingly delicate and costly maintenance. To each type of fraud there is a particular type of defense which, on the one hand, increases the complexity and the cost of the apparatus and, on the other, leads the defrauders to resort to increasingly powerful and damaging means. At present, the losses due to vandalism and fraud are considerable. As an exaple, about 20% of telephone traffic carried by public telephones is fraudulent. Repairs due to vandalism and the loss of revenue due to frauds have reached several hundred million Francs for a total of more than one hundred thousand apparatuses.
Remote surveillance of these apparatuses might be based on the analysis of the number of basic charge unities elapsed during a predetermined period for each public telephone, as described in European patent EP-B-0,004,497. In this case, remote surveillance only notes the anomalies after the event and does not allow immediate action. In other cases, such as the use of signalling contacts, remote surveillance is limited since it is dependent on the normal intervention by the personnel; it can therefore only be used outside service hours, thus reducing its effectiveness.
From the point of view of management and daily operation, the systems currently in service offer the following disadvantages:
Operating anomalies, faults and unusual or fraudulent acts by the user are neither detected, nor identified, nor even signalled.
The collection of revenue by coin box collection staff poses a considerable verification problem, inadequately dealt with by the existing procedure which is inefficient and cumbersome owing to the fact that the coin boxes are sealed. Memory coin boxes, such as described in European patent application EP-A-0,041,457, provide a solution to this problem, but at the price of a complex, inflexible and costly operating procedure.
Accounting and technical operating data concerning the apparatuses are currently analyzed by means of hightly dispersed ressources making collection and utilization of these data difficult and laborious. The collection and analysis of the various operating indicators are so complex that in practice, the control services use this ressource sparingly.